Chemistry and Chemical Biology ETDs

Publication Date

Fall 11-13-2017

Abstract

Cell signaling translates extracellular signals into intracellular processes that carry out cellular functions. The introduction of artificial signaling networks using synthetic biology methods has facilitated the investigation of signaling mechanisms and the generation of novel cell functions. Several synthetic biology methods that are based on chemical controls have been developed to provide precise temporal regulation. In my dissertation, we constructed new synthetic biology engineering strategies to control tailored cellular events.

Described in Chapter 2, we developed a new chemical strategy to generate de novo signaling pathways that link a signaling molecule, H2O2, to different downstream cellular events in mammalian cells. This approach combines the reactivity-based H2O2 sensing with the chemically induced proximity (CIP) technology. By chemically modifying a CIP inducer, abscisic acid (ABA), with an H2O2-sensitive boronate ester probe, novel H2O2 signaling pathways were engineered to induce transcription, protein translocation and membrane ruffle formation upon exogenous or endogenous H2O2 stimulation. This strategy has also been successfully applied to gibberellic acid (GA)-based CIP system, which provides the potential to build signaling networks based on orthogonal cell stimuli.

Encouraged from development of the H2O2-based strategy, described in chapter 3, we developed another new synthetic biology strategy which integrated chemical reactivity sensing and CIP methods to generate artificial Fe2+ signaling circuitry to control tailored cellular events in mammalian cells. A new probe ABA-FE18 (Fe2+-sensing and protein dimerization) derived from ABA was developed and used to control gene activation, signal transduction, and cytoskeletal remodeling in response to Fe2+. Combining Fe2+ and H2O2sensing with ABA and GA CIP systems, signal circuitries were designed to implement “AND” and “OR” biologic gates that enables mammalian cells to convert different combinations of Fe2+ and H2O2signals into pre-defined biological outputs.

Described in the last chapter, we engineered a unique CIP method based on mutant antibody VL domain using a fluorogenic malachite green derivative as the inducer, which gives fluorescent signals upon VL domain dimerization while simultaneously inducing downstream biological effects.

Language

English

Keywords

biologic gate, biosensor, cell signaling, chemically induced proximity, hydrogen peroxide, labile iron

Document Type

Dissertation

Degree Name

Chemistry

Level of Degree

Doctoral

Department Name

Department of Chemistry and Chemical Biology

First Committee Member (Chair)

Fu-Sen Liang

Second Committee Member

Changjian Feng

Third Committee Member

Lina Cui

Fourth Committee Member

Wei Wang

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